Where should i start....

Aside from the sharingan and the chidori and being geniuses....

Well lets see....

Well if i remember correctly Kakashi said in the very beginning that "Many of my friends' names are engraved on that rock," when he showed his team the rock with the "heroes" of konohana. Possibly all of his friends names are on that rock and possibly his parents, like many other shinobi, were killed fighting the Kyubi. This makes it possibe that he grew up with no loved ones or as they say in "Naruto," "people that are precious to you." Which would make him similar to sasuke losing his whole family. But besides that the same attitude, as gai said that sasuke reminded him of kakashi as a kid. (btw this is unlike naruto who never had parents,where as sasuke and kakashi had their loved ones taken from them with their own eyes )